藻粉在土壤中矿化进程及对油麦菜肥效研究

The Mineralization of Dried Algae Powder in Soil and Its Application in the Production of Lettuce

文章采用室内恒温培养法模拟藻粉在土壤中降解矿化过程,然后采用室外容器培养法,比较了藻粉和缓释肥对油麦菜幼苗生长的影响。结果表明:(1)藻粉处理组CO2释放规律为前14 d快速释放,后期变缓。经过131 d的培养,藻粉处理组土壤中有机碳较对照组最多增加了2.76 g/kg。(2)藻粉中氮素在土壤中先矿化成氨氮,后逐渐转化成亚硝氮,最终变为硝氮,藻粉矿化过程中有效氮含量呈逐渐上升趋势,整个培养过程中几乎没有氮损失。(3)经过131 d,藻粉处理组土壤中有效磷和总磷含量较对照组均显著增加。(4)实验测定第35天藻粉影响下土壤中与碳氮磷相关的酶活性较CK显著增加。(5)藻粉对油麦菜生物量、光合活性、叶绿素含量和氮磷供给与缓释肥没有显著性差异。综上所述,藻粉是一种易分解矿化的有机物料,在土壤中缓慢分解释放CO_2、有效氮和有效磷,并能增加土壤有机碳、氮和磷含量,同时改善土壤微生物酶活性,对油麦菜生长具有促进作用,和缓释肥肥效一样。实验得出有效氮施加量为87.7 kg/hm2时,油麦菜生物量达到最大值,对应藻粉的施用量为1 t/hm^2。

This paper reports results of a laboratory microcosm experiments which were set to study the mineralization of dried algae powder（DAP） in the soil. It involved the use of growth chambers of lettuce seedlings that were planted, and their growth monitored to compare the effect of DAP and commercial slow-release fertilizer（SRF）. Results showed that the mineralization of algae to CO2 was quickly at the beginning, then slowed down after 14 days, and the soil organic carbon was increased with amendments of algae biomass after 131 days, in which the most increase is 2.76 g/kg. There was initial release of total inorganic N as NH4＋-N, which was then converted into NO2--N and lastly into NO3--N. Total inorganic N increased gradually with time and there was no nitrogen loss during the whole incubation period. After incubation, the total P and available P of soil with amendments of algae increased. The soil biological activities differed considerably between CK and DAP treatments. The N and P supplied to lettuce by algae biomass was equal to that supplied by slow release fertilizer and both equally increased the plant yield during the study. This result demonstrated that algae biomass is easy to mineralize into CO2, available N and available P, and it increased the TOC, TN, TP and microbial activity of soil at the same time. The results showed its high potential in direct application for lettuce production, with the best field application rate of 87.7 kg available N hm（-2）,which was equals to 1 t/hm2 on algae biomass usage.